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MG MGB Technical - Homemade Tire Truing Machine

Hey, Guys - I just finished a year-long quest for a smooth ride. In the process, I created a new machine for curing out-of-roundness in tires. Thought you might like to see what I did, so I posted it on my web site. -G.

http://www.everity.com/~ggoodspe/volvo/WheelBalancing.htm
Glenn G

The point about locating via the stud holes rather than the badge hole is very important.
David Witham

Thanks Glenn: A very interesting approach for tire truing to cure vibration. There are one or two shops in our area that can shave tires. Some race shops use tire shavers to cut the thread down on new tires.

Clifton
Clifton Gordon

Glenn, interesting solution to your problem. I am very familiar with the old spin balancer you have, used to have a similar unit at my dad's shop. It came with a device that clamped into the wheel rim and contained a system of weights that the operator could adjust and move while the wheel was spinning, the read out the amount of weight and the position from the dial when good balance was achieved. As a kid I really never did get the hang of it well, always use the old bubble balancer for my tires and had good results. There is a good description of this old system on this web page. http://www.ntahc.org/techtips/WheelBalance1.htm
As far as initial balancing, if you try a bubble balancer to get the initial weight and then take two weights about 1/2 to 1 ounce heavier in total to the one required and split them placing them equi distant from the center of the out of balance spot and adjusting them until you get a balanced bubble again you usually have better dynamic balance as well. It's an old trick the men in my dad's shop taught me as a kid back in the 60's. Also if the tire is more than about 1 and 1/2 ounces out of balance it's probably a good idea to use 4 small weights and position them two on each side of the rim to get a better dynamic balance. This old technology isn't used much anymore, but with wires or rostyles it's a good thing to know as neigher work well on modern balancing machines.
Bill Young

"The point about locating via the stud holes rather than the badge hole is very important"

It's also been repeated many times. MGB wheels were designed before computer balancing machines, the random hole in the middle simply isn't adequate. Most computer balancers do seem to have an adapter for using the stud holes. You might then think that computer balancing machines would be ideal for balancing centre-lock wheels, but they can't do that either, as none I have found have the special adapter that is required so the wheel is held on the same faces as when on the hub. I wish I could find a spin-balancer, I have had my V8 wheels repeatedly rebalanced in the past but can't get rid of a vibration that fades in and out at a predictable rate at speeds of 65 and over.
Paul Hunt

Glen, you need to get the rest of the spin balancer. There were two styles, one is as Bill mentions above, the other came with a sensor and strobe light. the sensor sat on the floor and was in contact with the lower control arm. The heavy side of the tire would trigger the stobe sensor when it was at the bottom of the wheel. You aim the strobe at the wheel and it will freeze the motion when triggered. You then look at the position of the tire valve to use as a reference as to where to put the weights. It works quite well as does the one Bill describes. Word of warning, the one Bill has with the adjustable weights has been known to fly apart at speed. The nice part of these was that you balanced everything at once including the brake rotor, front hub, etc. My local Olds dealer taught me their trick for the drive wheels on my Olds, Leave one tire on the ground and put the car in gear and run it up to 40 MPH on the speedo, the wheel that is raised will be going 80 MPH. The on the car balancers were the only way to get the shimmey out of the early Toronados.
John H

This thread was discussed on 22/10/2008

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